Archive for January, 2008

Probability and Statistics with Mathematica and Excel

Mathematica:
Binomial: \binom{a}{b} \Rightarrow $Binomial$[n,m] Binomial

Average: \frac{1}{n} \cdot \sum_{i=1}^{n}x_i \Rightarrow $Mean$[\{x_1,x_2,\hdots,x_n\}] Mean

Median:\text{Median}[\{x_1,x_2,\hdots,x_n\}] Median

Modus: \text{Commonest}[\{x_1,x_2,\hdots,x_n\}] Commonest

Excel:
Binomial Distribution: P(X = k) = \binom{n}{k} \cdot p^k \cdot q^{n-k} \Rightarrow $binomdist$(k$,$n$,$p$,true/false$)

Poisson: P(X = k) = \frac{\mu^k}{k!}\cdot e^{-\mu} \Rightarrow $poisson$(\mu$,$k)

Hypergeometric Distribution: P(X=k) = \frac{\binom{M}{k} \cdot \binom{N-M}{n-k}}{\binom{N}{n}} \Rightarrow $hypergeomdist$(k$,$M$,$N$,$n)

Normal Distribution: \Phi_{\mu,\sigma}(x) = \Phi \left( \frac{x-\mu}{\sigma} \right) \Rightarrow $normdist$(x,\mu,\sigma,$true/false$)

\Rightarrow $norminv$(P(X),0,1)

Standard Deviation: \sigma := \sqrt{\frac{1}{n} \sum_{i=1}^{n}(x_i – \bar{x})^2} \Rightarrow $stdev$(x_1,x_2,\hdots,x_n)

Experimental Standard Deviation: \sigma := \sqrt{\frac{1}{n-1} \sum_{i=1}^{n}(x_i – \bar{x})^2} \Rightarrow $stdevp$(x_1,x_2,\hdots,x_n)

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Thomas Post on January 31st 2008 in Math

New MacBook Air

MacBook Air Closed
MacBook Air Side
MacBook Air Backside

Last week Apple introduced the new MacBook Air the world’s thinnest notebook. The world’s thinnest means 4 mm in the front to 19 mm in the back. I think thats just awesome! That’s so thin it’s unimaginable. But this size has its costs. The MacBook Air has no FireWire (400 nor 800), no Ethernet and no Audio-In. It has just one USB 2.0 Port, a micro-DVI Port and a headphone jacket. Now how can you connect it to the internet? The product name told it already. You connect it over the Air with 802.11n.

Based on the size it hasn’t a CD/DVD-ROM drive built in. You can just plug in (on that single USB port you have) an external one. I think thats a good solution in combination with that “Remote Disc” feature. Because last time I used the CD/DVD-ROM drive of my MacBook Pro was when i installed Mac OS 10.5.

Finally the price: The standard Core 2 Duo 1.6 GHz model with 80GB 1.8″ HDD and 2GB RAM costs $1799. The 1.8GHz C2D costs $300 extra. For a SSD you will pay $999 extra. That makes it a really expensive notebook.

Conclusion
If you have the money for it and it’s not your only computer its a glorious ultra portable mac!

Rating: ★★★★★★★★☆☆ (-1 for the price and -1 for the missing ports)

Now watch the ad below or have a look at apple’s homepage

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Thomas Post on January 21st 2008 in Stuff

Apple Address Book vCard Export v1.1

vCardExporter Icon

Today I can release a new version of vCardExporter with a few bug-fixes.

  • Re-import into Address Book works now (no “No importable cards were found.” message will appear)
  • New application icon added
  • Window title and opacity adjusted

I hope this version will do it’s job better then the old.
Download: vCardExporter 1.1
Application description

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Thomas Post on January 13th 2008 in Stuff

Rush Hour 3

Rush Hour 3

Last sunday evening I took some time to watch “Rush Hour 3″ and it was better then I expected. The movie is very funny and amusing. It has some surprises, good jokes, an exciting story and beautiful playgrounds. The most time of the movie they are in Paris (have a look at the poster). You can seen a lot of the wonderful places in Paris during the movie.

The story tells about Chief Inspector Lee’s brother. At the beginning he kills the ambassador which Lee should protect. That is the beginning of a manhunt to Paris. Lee and his adversary try to kill each other a view times. But no one can kill the other one because he is his brother. Although finally Lee’s brother will find a solution…

Detective James Carter is how ever not so correct and focus too much on the signoras. So it is not unexpected that he got in trouble with them and finally with Lee.

Rating: ★★★★★★½☆☆☆
IMDB Link

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Thomas Post on January 9th 2008 in Movies

Aliens vs Predator – Requiem

Aliens vs Predator - Requiem

The complete movie plays in a small country in the USA. (I forgot how it is called and it isn’t important). In the beginning everything is normal you see a few stories like a pizza currier felt in love, his brother returned from the prison, a women return from the army and a father goes deer hunting with his son. But then the predator ship with a nice alien – predator hybrid landed, the war begins and the people die off. In the end they blow up the whole city and more then 50% of the main characters are alive!! (that’s bad for a movie like this one, in this part AVP 1 was much better!).
Final scene is a bit confusing: The man who blew up the city brings the predator weapon to a women who tells something that the earth isn’t ready for it. Then he means that it isn’t for this world

All these fight scenes A vs P and specially AP vs P (pleas next time more of it) with their special effects are quite good! There are a lot of good scenes in the hospital. Although form my flavor in this part of AVP there are insufficient H.R.Giger styled locations. Finally I can say it’s nearly what I’ve expected and it was good entertainment but it won’t be a blockbuster movie.

Rating: ★★★★★½☆☆☆☆
IMDB Link

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Thomas Post on January 6th 2008 in Movies

latex for wordpress

Today I was wondering if it is possible to add \LaTeX support to my WordPress blog. First I got started with google and found this plugin. It needs dvipng which isn’t installed on my web-space. So I searched along for another plugin and found this one which is working great now! The installation is really simple, you need to create three directories and modify a few include paths in PHP files. Provided that you have installed latex, dvips, convert and identify on your web server.
Some examples:

  • \sqrt{\frac{1}{2}}
  • IC_F := \frac{\sum_{i=1}^{26} {n_i \choose 2}}{{n \choose 2}}
  • \int_{5}^{6}\frac{5}{2x-4}dx

or have a look at my first post with latex formulas in it.

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Thomas Post on January 4th 2008 in Regards

Helpfully functions in mathematica for cryptographic

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Thomas Post on January 4th 2008 in Math

iPhone Firmware 1.1.2

After I got some problems with anySIM during the update from 1.1.1 to 1.1.2 (be sure to be in airplane mode during unlocking with anySIM and installing iWorld from the Installer to get SMS and Phone working) it is now finally working. :-)
The main fixes for me in this version are:

  • Localized – keyboards and auto correction*
  • Receiving SMS’s from the mailbox
  • EDGE settings are now stored properly*
  • TIFF exploit fixed (now I’m sleeping better) *

However that’s all it’s not really more. Or have I forgotten something? I don’t think so. In the daily usage it’s not a big change, maybe it is a bit faster and more stable but that’s all.The problems I get during the update (missed up that airplane mode thing) were it not worth. So I would not do it again!

* workaround for 1.1.1 is also available

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Thomas Post on January 3rd 2008 in iPhone

StartupSound.PrefPane

You are on a train, in a meeting or at the auditorium and you would start your mac. Press the power button and then BOOOM… oh i hate this moments! Everyone is looking at you, thats sometimes a bit embarrassing.Now i found a solution: StartupSound.PrefPane from Arcana Research. That’s a really good utility! Thx!

Rating: ★★★★★★★★★★

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Thomas Post on January 3rd 2008 in Regards

Apple Address Book vCard Export

Last autumn I was sad about the Apple Address Book’s vCard export function. If you d’ like to export more then one vCard, Address Book puts them all together in one file. But i d’ like to have them in separate files. So I took a bit of time and wrote this tiny application.
vCard Exporter

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Thomas Post on January 3rd 2008 in Stuff